Feeling SAD? The dark side of winter

For some, lack of sunlight triggers fatigue, anxiety and weight gain

In this story: Winter blues Three or four hours of sunlight RELATED STORIES, SITES

By Douglas Herbert, CNN.com writer

LONDON, England (CNN) -- April has been called the cruellest month. But millions of sun-deprived northern Europeans might beg to differ: For them, it's the dark, dreary interlude from October to March that can wreak the greatest psychological toll on their biological clocks -- and their mood.

As Europe prepares to turn its clocks back this weekend, the daylight-shaving exercise looms for many as more than a mere temporal tweaking.

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For the estimated two percent of northern Europeans who suffer from so-called Seasonal Affected Disorder (SAD), the annual descent into the heart of hibernal darkness can mean months of distress and disruption to their normal routines.

Symptoms range from fatigue, despair and depression to binge-eating and joint pain. The symptoms tend to be most aggravated in months when the days are shortest -- around the December winter solstice -- and in the long winter lull following the heightened activity of the holiday period.

Left untreated, the disorder can become debilitating and, in dire cases, sufferers have been known to take their lives.

Shakespeare famously wrote "a sad tale's best for winter."

But it was not until much more recently -- the last decade or so -- that science has started to seriously classify SAD as a bona fide mental illness, worthy of its own specialists and treatments.

In graver cases, people suffering from SAD might feel overwhelmed and unable to cope with even the simplest tasks, like going outside.

Ironically, the disorder is often less prevalent at very high latitudes, where light-reflecting snow helps to alleviate the sense of gloom.

An additional 10 percent of people experience "winter blues" -- a milder form of depression that health experts say is triggered by subtle shifts in brain chemistry caused by the absence of bright light associated with the spring and summer months.

About 15 percent of those diagnosed with depression eventually commit suicide, according to Patricia White, a spokeswoman for the UK-based Depression Alliance.

Of the 6,000 suicides in the UK each year, more than 70 percent are depression-related, of which an unknown number are thought to be tied to seasonally induced mood swings.

The incidence of SAD, experts say, tends to increase as one moves further from the equator, the invisible line that encircles the Earth, dividing it into two equal hemispheres.

People with low levels of seratonin -- a hormone produced by the brain that helps to alleviate feelings of fear, sadness and anxiety -- may also be especially susceptible to winter depression.

Professor Fred Holsten, a psychiatry lecturer at the University of Bergen in Norway, said about three to four percent of his country's population experiences serious enough forms of winter depression that they are unable to function normally without medication or other forms of treatment.

In Bergen itself, about 600 kilometres west of the capital Oslo, the dark season sets in early October and extends until the end of March. During the Christmas holiday season, the region gets only about three or four hours of sunlight a day.

"We are not only situated very far north, but we have cloudy weather as well," said Holsten. He noted that many people continue to suffer for a few weeks from the residual effects of winter blues even after the return of bright sunlight in April.

The most prevalent form of treatment for winter depression is light therapy, in which sufferers sit in front of a "light box" with fluorescent bulbs to simulate natural sunlight.

Users typically sit in front of the light for up to 45 minutes daily throughout the darker months. During the sessions, they can read or even watch television -- so long as the light from the bulbs hits the retina of their eyes.

Other recommended treatments include aromatherapy, like the use of citrus oils that remind users of sunny climates, or an herbal supplement such as St. John's Wort. Experts warn, however, that the latter should never be used in conjunction with light therapy, since it could produce an adverse side-effect.

Many sufferers, at least those who can afford to do so, seek to alleviate their symptoms by escaping on holiday to the sun.

In other places, where one might expect winter depression to bite hard and deep, the population seeks uplift in other avenues of entertainment.

Judith Perry, a research fellow at the University of Tromso, situated above the Arctic Circle 900 miles north of Oslo, said students in the town temper the climatic dreariness with endless festivities. From November 20 to January 20, the sun does not rise above the horizon. In November, residents must endure 18 hours of night time darkness a day.

"Christmas is a huge season," Perry said. "Everyone goes to three or four parties a week."

Perry also believes cultural acclimation plays a role in the proportionally low incidence of winter depression in Norway's far north.

"Norwegians have a real frontier kind of attitude. Part of their heritage is to tackle what's difficult and not to complain. That's sort of part of the culture here."

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Seasonal Affective Disorder Association
Depression Alliance
World Health Organization
Winter Depression Homepage (University of Tromso, Norway)

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